Homework Assignment
•Suppose a 100x100 array S is distributed by blocks across four processors, so that each contains a 50x50 subarray. At each position S[i,j] is updated by the sum of its 8 nearest neighbors:
•S’[i,j]=(S[i-1,j-1]+S[i-1,j]+S[i-1,j+1]+S[i,j+1]+S[i+1,j+1]
• +S[i+1,j]+S[i+1,j-1]+S[i,j-1])/8;
•If each processor updates its own elements, how many messages must are produced to maintain concurrency for a directory based CC-NUMA? •HINT: Assume that an extra row and column, initialized to zero, surrounds A, A is allocated in rmo, and storage for S alternates with S’